Shock absorbing system for yarn delivery apparatus



June 7, 1966 w. E. HAWKINS 3,254,820

SHOCK ABSORBING SYSTEM FOR YARN DELIVERY APPARATUS Filed June 15, 1964 hINVENTOR BY 27M K United States Patent 3,254,820 SHOCK ABSORBING SYSTEMFOR YARN DELIVERY APPARATUS William Edward Hawkins, Seaford, Del.,assignor to E. I. du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware Filed June 15, 1964, Ser. No. 375,186

2 Claims. (Cl. 226-172) This invention relates to apparatus fordelivering a running length of yarn or tow composed of a plurality ofyarns and more particularly to means for handling running lengths ofyarns or tow at high speeds for delivery onto conveyor belts or intocontainers from which the lengths are readily removed.

Since a yarn delivery device must pull the yarn or tow from a sourceassisted only by gravity, difliculty is usually encountered in staticgeneration, yarn breakage, wrap formation, tension variation and thelike. These diificulties are particularly serious when processing a towcomposed of a large number of synthetic filaments or yarn ends. Onemethod of yarn delivery which avoids many of these difliculties is tofeed the yarn or tow into a nip formed by two endless belts running inclose proximity. From the nip, the yarn is guided into a suitablecontainer or disposed of in any other desirable fashion.

Yarn delivery apparatus of this type (referred to in the art as a beltpiddler) is disclosed in U.S. Patent 3,061,164 to Valerius, issued onOctober 30, 1962, and U.S. Patent 2,805,765 to Saum et al., issued onSeptember 10, 1957. While the belt piddlers described in thesereferences are suitable for relatively low speed operation and may evenbe operated for short periods at higher speeds, they are not suitablefor continuous commercial operation at high speeds, i.e., of the orderof 1,000 to 1,500 yards per minute. At such higher speeds, the prior artdevices tend to create irregularities in the delivery of the yarn or towwhich cannot be overcome by the mere use of positive biasing meansacting on the nip formed by the two endless belts.

An object of this invention is to provide an improved belt piddler whichis suitable for delivery of tow or rope into a container in a uniformmanner at high speed. Other objects will become apparent from thedescription hereinafter.

The objects of this invention are accomplished by a yarn delivery devicewhich comprises two endless belts each mounted in vertical, spatialproximity on driving means and tension rolls and having a pair ofoppositely disposed compression rolls which are adapted to contactthetwo endless belts in such a manner that a short nip is formed by thebelts for gripping and advancing the yarn or tow. The tension rolls havemeans associated therewith which maintain the endless belts in a tautrelationship and absorb the shock created by the high speed ofoperation. Similarly, at least one of the compression rolls is providedwith means which not only biases the compression roll to maintain thenip but also absorbs the resultant shock.

The accomplishment of these objectives can be seen by reference to thefigures given for illustrative purposes and to the description below:

FIGURE 1 is a front view of the belt piddler; and,

FIGURE 2 is a schematic front view of the preferred embodiment of thisinvention.

With reference to FIGURE 1, there are two endles belts, designated 1 and2, which are mounted in such a manner as to come into close proximityand form a short nip during a part of their respective travel. Belt 1 ismounted on rollers 3 and 4 being driven by roller 3 and belt 2 issimilarly mounted on rollers 5 and 6 being driven by roller 5. Thesebelts are made to contact or 3,254,820 Patented June 7, 1966 almostcontact each other by the placement of compression rollers 7 and 8.Idler rollers 9 and 10 serve to fix the angle at which belts 1 and 2leave compression rollers 7 and 8. The angle at which the belts approachthe compression rollers is, of course,-fixed by the placement of driverollers 3 and 5 relative to compression rollers 7 and 8. The driverollers and idler rollers 9 and 10 are positioned so that a relativelyshort nip is formed and.

so there is some angularity of the belts around compression rollers 7and 8.

As illustrated in FIGURE 2, roller 6 is mounted on swingarm 11 which ispivoted at 12, pivot 12 being attached to a supporting frame, not shown.Air cylinder 13 is pivotally attached to swingarm 11 and the supportingframe. Compressed air may be introduced at connection 14 to force piston15 downwardly, thereby applying tension to belt 2. Similarly, airpressure may be applied at connection 16 to lift roller 6 to facilitateplacement or removal of belt 2. A shock absorber 17 is also pivotallyattached to swingarm 11 and the supporting frame as illustrated. In asimilar fashion, roller 4 is mounted on swingarm 18 with attached aircylinder 19 and shock absorber 20.

Compression roller 8 is mounted on swingarm 21 which is pivotallysupported at 22. Air cylinder 24 is pivotally attached to extension 23of swingarm 21 and to the supporting frame. Compressed air may beapplied to air cylinder 24 to move roller 8 toward fixed roller 7 andthus from a nip between belts 1 and 2 at this point. A shock absorber 25is pivotally attached to swingarm 21 and the supporting frame.

In operation, the yarn or tow is fed from a source (not shown) overroller 26 and then into the nip formed by endless belts 1 and 2 whichact to forward it downwardly into a rotating can 28 or other suitablecontainer in a uniform fashion so that it can be easily withdrawn at alater time.

The roller diameters may be varied as desired but for most purposesrollers 3, 4, 5 and 6 may suitably be about 6 inches in diameter androllers 7, 8, 9 and 10 about 4 inches in diameter. Drive rollers 3 and 5are preferably geared together so that no speed differential existsbetween the two. The belt width may vary somewhat depending on the typeof yarn or tow being processed but a 6-inch belt width is usuallysatisfactory for processing tow having a denier in the order of 100,000.The placement of the tension rollers relative to the drive rollers maybe varied in accordance with other conditions but these rollers maysuitably be placed about 30 inches apart, center to center.

While the type of belt may be selected to suit the par- The shockabsorbers employed are conventional, com-- mercially availablefluid-type shock absorbers. Double action shock absorbers having a1.5-inch bore and a 4-inch stroke are suitable for tension rollers 4 and6. Shock absorber 25 is preferably a single-action shock absorber of1.5-inch bore and 3-inch stroke. This shock absorber is provided with acheck valve which permits free flow of liquid when roller 8 is movedtoward roller 7 but closes when the roller is moved in the reversedirection causing the fluid to be forced through the needle valve of theshock absorber, thus retarding movement in this direction only.Preferably, all of the shock absorbers are equipped with adjustableneedle valves so that the retarding action may be adjusted as desired..

The nip formed by the belts should be relatively short,

although contact of the belt and tow may be maintained for some distanceas the tow passes between rollers 7 and 8 due to slight expansion of thefilament bundle as the pressure is relieved. After leaving rollers7 and8, the belts gradually separate due'to the angularity of the beltsrelative to the vertical path oflthe tow. The angularity should besubstantially the same for both belts to facilitate release of the towfrom both belt surfaces and prevent wraps on the belts. The angle of thebelt relative to the vertical path of the tow as the belt passesdownwardly from the compression roll may suitably be about 0.5

The pressure on the air cylinders may be adjusted in accordance withother processing conditions; however, a

' pressure of 60 to 80 psi. is usually suitable for cylinder 24 while apressureof 35 to 60 psi. may be employed for air cylinders 16 and 19.

The yarn delivery. device of this invention is useful in handlingrunning yarn ends or tows of any material, synthetic or natural.

The apparatus of this invention provides continuous piddling of yarn ortow at speeds of 1,000 to 1,500 yards per minute under commercialconditions with freedom from formation of wraps on the belt and with asatisfactory laydown of the tow in the container. By contrast, when theprior art devices are operated at this speed, the action of the towbecomes erratic with the irregular laydown in the containerand.occasional loops falling over the edgeof the container. In addition,frequent wraps on the belt are encountered so that commercial ope-rationis impractical.

Several critical improvements contribute to the superior operability ofthe apparatus of this invention. The combination of air cylinder 24 .andshock absorber 25 cooperate to provide smooth running of the tow betweencompression rollers 7 and .8 While air cylinders 19 and 24 and shockabsorbers 13 and 20 promote smooth running of the belts on the rollers.

Since many different embodiments of the invention may bemade withoutdeparting from the spirit and scope thereof, it is to be understood thatthe invention is not limited by the specific illustrations except to theextent defined in the following claims.

What is claimed is:

1. A yarn delivery apparatus for handling running lengths of yarn or towat high speeds which comprises drive means, tension rollers verticallydisposed from said drive means, two endless belts located in spatialproximity and mounted upon said drive means and tension rollers, an aircylinder and a double action shock absorber operably connected to eachof said tension rollers to maintain said endless belts in a tautrelationship and to absorb the shock created, a'pair of oppositelydisposed compression rollers contacting said endless belts to form ashort nip in said endless belts for gripping and advancing said yarn ortow, and an air cylinder and a single action shock absorber associatedwith at least one of said compression rollers to bias said compressionrollers in maintaining said nip and to absorb the resultant shock,whereby the yarn or tow is vertically delivered with regular laydown.

2. The yarn delivery apparatus of claim 1 wherein said drive means aregeared together in such a manner that the surface speed of said twoendless belts is equal.

References Cited by the Examiner UNITED STATES PATENTS 1,917,659 7/1933Marshall 198165 2,805,765 9/1957 Saum 226-172 2,858,936 11/1958 Ogden198-208 3,046,771 7/1962 Bailey -198-l65 X M. HENSON WOOD, JR., PrimaryExaminer.

ROBERT B. REEVES, Examiner.

R. A. SCHACHER, Assistant Examiner.

